Combined carburetor choke and nozzle



" Nov. 11, 1952 s. M. UDALE COMBINED CARBURETOR CHOKE AND NOZZLE Filed June 8, 1949 INVEN TOR.

Patented Nov. 11, 1952 UNITED STATES PATENT OFFICE COMBINED CARBURETOR CHOKE NOZZLE Stanley M. Udale, Detroit, Mich., assignor to George M. Holley and Earl Holley:

Application June 8, 1949, Serial No. 97,857

. l Theobject of this invention is to improve the combined fuel nozzle and choke valve located in a Venturi as shown in the co-pending Kittler and Winter application Serial No. 58,748 filed November 6, 1948, now Patent No. 2,538,569, and Egerer, Serial No. 94,446 filed May 20, 1949, now Patent No. 2,538,559.

The problem is to make achoke valve serve: (l) as a choke valve when closed, (2 as part of the Venturi mixing chamber when open, and (3) as part of the fuel nozzle at all times. The fuel a must discharge equally on both sides of the choke valve when "the choke valve is wide open. When closed the fuel outlet on the upstream side will be at atmospheric pressure and will tend to bleed the fuel outlets located onthe downstream side of the choke valve. To avoid this the choke valve 'must therefore act also as a fuel valve which positively cuts off these outlets so as to'increase the fuel flow as the air fiow is restricted. On the other hand, at wide open throttle both sides must discharge fuel equally. Maximum fuel flow must be obtained when air flow is choked, and uniform and equally divided fuel flow must be obtained when the choke valve is moved into its wide open position.

This type of carburetor has two similar Venturi mixture passages in parallel. The entire Venturi shape may be obtained from the streamlined choke valve without any actual Venturi.

Fig. 1 shows the preferred form of my invention (choke valve open) Fig. 2 shows a partial view taken at 90 to Fig. 1 (choke valve open) Fig. 3 shows a modified form of the choke valve shown in Figs. 1 and 2.

Fig. 4 shows an alternative construction.

In Figs. 1 and 2, I is the air entrance, I2 is the choke valve of streamlined shape. I4 is the throat of the venturi in which the choke valve is installed. It is a hollow choke operating shaft mounted on the stationary hollow shaft 60 which acts also as the fuel nozzle. 19 (Fig. 3) is one of two slots in the choke valve I2 by which it is moved. I! is one of two tongues extendin from the right hand end of the hollow shaft l6 which engages with one of the slots l9.

On the left hand side of choke valve l2 (Fig. 2) is a fuel opening 31 which is only in alignment with the fuel opening 41 of the nozzle 60 when the choke valve [2 is in its Wide open position,

(as shown) 43 is the opposite opening in the right hand side" of choke valve l2 and this is also in alignment with the port 45 which communicates with the middle of the nozzle 60.

4 Claims. (Cl. 2 61--.44)

the opening 31.

When the choke valve I2 is movedrclockwise (Fig. 2) the opening 4'3 discharges more. and more fuel as the air flow is restricted. Opening 3.1' quickly becomes inactive as the opening- 41, in the fuel nozzle 60, ceases to be in alignment with In Fig. 3 openings 3|, 3'42, 33 35, 25, 28 and '29 are all in operation when the choke is wide open. When there are a number of openingaas shown, if the mixture inthe miiiture outlet should not be uniformly divided then the desired uniformity may easily be-s'ecured by having three openings on one side and four openingson the other. The choke valve i2 is operated by choke lever 22.

The throttle 3B, controlled by the throttle lever 4 I, mountedon' the throttle shaft 39, controls the mixture outlet'23 and also the low speed fuel passage 40, through the low speed fuel outlets 42 and 44. Fuel": is supplied from the constant level chamber having al'constant level line 49 througha'inaster' fuel restriction 48, up the well 50, down the inclined passage 62 into the center of the nozzle 60.

Air in the air entrance Iii flows down the inclined tube 52, into the well 5|), through the tube 54 in a well known manner. 7

The low speed fuel is drawn off through passage 56. 58 is an air vent to break the syphon 58-40 which would otherwise exist.

In Fig. 4 the streamlined choke valve 10,mounted on a solid shaft 12, is located vertically above the nozzle 14. The shaft 12 is pinned to the valve 10 by a pin". The fuel outlet 16 lines up (when the chokeis wide open) with the fuel outlet orifice 82. The other fuel outlet orifice. 18 is subject to the suction created by the gap in the choke valve, which gap permits the choke valve to close. The nozzle 74 actsas a wide open stop for the choke valve Til.

Operation When the choke is as shown in Fig. 1 it acts as a bar nozzle and the size of orifice 3 1 and-the size of orifice 43 are adjusted to correct distribution trouble especially when the choke shaft 60 and throttle shaft 39 are at right angles to the internal combustion engine crankshaft. This is the most convenient arrangement for the dash control.

Distribution isadj'usted by making one or the other of the fuel openings 31 or 43 larger than the other.

In the case of Fig. 3 there are three openings on one side and four openings on the other side. This is a more convenient construction for' adjusting the distribution equally between the front and rear three cylinders of a six cylinder engine with the axis of the choke valve at 90 to the axis of the crankshaft.

In Fig. 4 the opening 16 is adjusted with reference to the opening 18 so that fuel is discharged equally on both sides of the streamlined choke valve 18;.

WhatI claim is:

1. A carburetor for an internal combustion engine having an air entrance, a mixture outlet and a throttle valve therein, the improvement which consists in a fuel nozzle projecting into the center of the air stream and at right angles thereto, a streamlined choke valve r0.- tatably mounted on an axis at right angles to the air stream and in the center thereof. and adjacent said fuel nozzle, fuel openings in said choke valve, corresponding openings in said. nozzle so located that when the choke valve is wide open the fuel discharges from both s des of said choke valve. and from the downstream side. only when the choke valve is closed.

2. A carburetor for an internal combustion engine. having an air entrance, a mixture outlet and a throttle valve therein, the. improvement which consists in a fuel nozzle projecting into the center of the air stream and at right angles thereto, a streamlined choke valve mounted on a rotatable. shaft also located in the center of the. air stream on an axis parallel to the nozzle and. upstream thereof, a recess. in the choke valve permitting the choke valve to close, an opening through the choke valve on the opposite side .to said recess, fuel openings in'said nozzle one of which lines up with the opening through the choke valve, said nozzle acting as the wide open stop for said. choke valve.

3.. A. carburetor for an internal combustion engine having an air entrance, a mixture outlet anda throttle valve therein, the improvement 'axis of said choke valve, said fuel nozzle being so located that when the choke valve is closed the nozzle discharges downstream of. the choke valve and when the choke valve is open it discharges equally on both sides of said choke valve responsive to the suction created by said wedge shaped disc.

4. A carburetor for an internal combustion engine having an air entrance, a mixture outlet and a throttle valve therein, the improvement which consists in a fuel nozzle projecting into the center of the air stream, a choke shaft also located in the middle of the air stream and at right angles thereto, a substantially circular disc choke valve mounted thereon and so located that when. wide open. it engages with said nozzle as a stop and divides, the discharge from the nozzle equally and when closed subjects the nozzle to full engine suction.

STANLEY M. UDALE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

